Knowledge about 7 types of plastic
Plastic number 1 is called Polyethylene Terephthalate (PET or PETE). It is a clear, hard plastic that is impact resistant, not easily broken, and has good gas permeability. It is used to make bottles for drinking water, vegetable oil, etc. It can be recycled into fibers for making sweaters, carpets, and synthetic fibers for stuffing pillows, etc.
Plastic number 2 is called High Density Polyethylene (HDPE). It is a tough and hard plastic that is quite hard but very flexible. It is resistant to chemicals and can be easily shaped. It is used to make milk bottles, water bottles, and packaging for cleaning products, shampoo, etc. It can be recycled into motor oil bottles, pipes, plastic crates, artificial wood, etc.
Plastic number 3 is called Polyvinylchloride or commonly known as PVC. It is used to make water pipes, clear hoses, food wrap films, plastic sheets for doors and windows, and artificial leather, etc. It can be recycled into water pipes or gutters for agriculture, traffic cones, furniture, plastic benches, tape cassettes, cables, artificial wood sheets, etc.
Plastic number 4 is called Low Density Polyethylene (LDPE). It is a soft, tough, stretchable, clear, durable plastic, but not very heat resistant. It is used to make food wrap and wrapping film, bread bags, cold food bags, and can be recycled into black garbage bags, shopping bags, trash cans, floor tiles, furniture, artificial wood, etc.
Plastic number 5 is called Polypropylene (PP) for short. It is a plastic that is clear, heat resistant, holds its shape, is tough and has good impact resistance. It is also resistant to chemicals and oil. It is used to make food containers such as boxes, bowls, plates, buckets, baskets, chilled water containers, sauce bottles, yogurt cups, medicine bottles. It can be recycled into car battery cases, car parts such as bumpers and oil funnels, tail lights, plastic brooms, brushes, etc.
Plastic number 6 is called Polystyrene (PS) for short. It is a clear plastic but brittle and easily broken. It is used to make containers for various items or foam food containers, etc. It can be recycled into clothes hangers, video boxes, rulers, thermometer bulbs, light switch panels, heat insulators, egg trays, and various tools and utensils.
Plastic number 7 does not have a specific name, but it is not one of the 6 plastics mentioned above, but is a remelted plastic.
Comparison table of melting points of different types of plastics
PET | HDPE | LDPE | PP | PS | PVC | |
Heat resistant | -20 to 60°C | 0 to 100 °C | -50 to 120 °C | -20 to 120 °C | -20 to 80 °C | -20 to 80 °C |
melting point(°C) | 260 | 120 | 115 | 165 | 240 | 80 |
Density(kg/m³) | 1370 | 941 | 920 | 855-946 | 1050 | 1380 |
Transparency | clear | opaque | opaque | good | clear | clear |
Hardness | high | ปานกลาง | low | high | Tall but fragile | high |
Shock resistant | very good | very good | very good | good | medium | good |
Heat resistant | medium | good | medium | good | medium | medium |
Prevents moisture from spreading | good | very good | good | very good | medium | medium |
recycled | Fibers for sweaters or carpets | Detergent bottle | Trash can | Car battery box | Clothes hanger | Traffic cone |